48-Channel 3D Flow Field Measurement and Control System for Compressors

In the field of modern high-performance turbomachinery research and development, the complex three-dimensional and unsteady flow within compressors remains a key bottleneck restricting the improvement of their aerodynamic performance. To thoroughly overcome this bottleneck, a university has successfully established a 48-channel three-dimensional aerodynamic flow field measurement and control system, with a pressure scanning valve array at its core. This system aims to achieve "transparent" insight into the internal flow field of compressors through ultra-high-density synchronous pressure sampling, providing unprecedented data support for deepening the understanding of flow mechanisms, validating design performance, and realizing active flow control.

Figure 1. Compressor Component Performance Map

I. System Core: Distributed High-Precision Pressure Scanning Valve Array

The design essence of this measurement and control system lies in its distributed, modular pressure scanning valve network. The system abandons traditional single-point or low-channel measurement modes and instead integrates multiple high-performance pressure scanning valves to form a high-speed data acquisition network with 48 independent channels. Each pressure scanning valve itself is a precision pressure acquisition center, integrating multiple silicon piezoresistive sensors that have undergone strict thermal and dynamic calibration, ensuring high-frequency response and high-precision measurement over a wide range.

During experiments, researchers meticulously arranged dozens of micro pressure taps at key aerodynamic locations such as the compressor casing inner wall, rotor passages, and stator blade surfaces. These pressure taps are precisely connected via high-pressure resistant, anti-interference micro-tubing to the various input ports of the pressure scanning valves located outside the test rig. When the compressor operates under different conditions, both steady-state wall static pressure distributions and transient total pressure fluctuations are captured by these pressure scanning valves with extremely high synchronization (microsecond-level synchronization accuracy) and sampling rates (up to hundreds of kHz per channel) and converted into digital signals. This architecture, centered on the pressure scanning valves, forms the physical foundation for achieving an "instantaneously frozen" measurement of the entire flow field.

II. Data Acquisition and Flow Field Reconstruction: From Pressure Data to 3D Flow Patterns

The powerful data acquisition capability of this system stems directly from the performance of its core component – the pressure scanning valves. In a typical test, the 48 channels of pressure scanning valves are triggered synchronously, acquiring massive amounts of spatiotemporally correlated pressure data within seconds. Processing and analyzing this data enables:

3D Pressure Field Reconstruction: Utilizing measurement points at different spatial locations, interpolation algorithms are used to reconstruct 3D static and total pressure distribution contour maps of specific compressor cross-sections.

Velocity and Vorticity Field Calculation: Based on the Euler equations or by measuring the pressure difference across opposing probes, the pressure data acquired by the scanning valves can be used to directly calculate the three-dimensional velocity vector and further derive the vorticity field characterizing vortex structures. This clearly reveals the spatiotemporal evolution of complex flow structures such as corner separations and tip leakage vortices.

Dynamic Stability Monitoring: When approaching the stall boundary, the pressure scanning valves can accurately capture low-frequency pressure fluctuations that the onset of rotating stall or surge, providing critical input for stability early warning and control.

Each data acquisition run is equivalent to performing a high-resolution "CT scan" of the internal flow field within the operating compressor, all relying entirely on the parallel processing capability of the 48 pressure scanning valve channels.

III. System Application and Closed-Loop Control: The Intelligent Engine Driving Design and Optimization

The high-fidelity experimental data generated by this system forms the core driver of the compressor R&D and optimization closed loop.
At the design validation level, the detailed pressure data obtained via the scanning valves provides a "gold standard" for the Verification and Validation (V&V) of Computational Fluid Dynamics (CFD) simulations, significantly enhancing the reliability of numerical predictions and accelerating the design iteration of new-generation high-efficiency blade profiles and flow passages.

In the realm of flow field optimization and closed-loop control, the system demonstrates its forward-looking value. By real-time analysis of the signal characteristics from key monitoring points (e.g., upstream of the rotor), the system can quickly identify early signs of flow instability. Subsequently, control algorithms generate commands to drive actuator mechanisms, such as plasma actuators or casing treatment valves, for active flow intervention. The effectiveness of this control loop is immediately sensed and evaluated by the pervasive pressure scanning valve network throughout the flow field, thereby forming a real-time closed-loop control system with the pressure scanning valves as its feedback core, ensuring the compressor operates safely and efficiently under optimal conditions.

Conclusion

The 48-channel 3D aerodynamic flow field measurement and control system successfully developed by the university represents a deep integration of high-performance pressure scanning valve array technology with the demands of complex flow field testing. This system is not only a powerful scientific observation tool but also an integrated platform that directly empowers compressor aerodynamic design, performance validation, and active control. It signifies that China's research capabilities in the field of experimental fluid mechanics for turbomachinery have reached a new level, laying a solid experimental foundation for breaking through the performance bottlenecks of next-generation aero-engines and gas turbines.

Figure 2. Coupled Simulation Model